Cushion and method of manufacture



May 21, 1963 E. P. HARRIS cusnron Am: uz'mon 011 MANUFACTURE 4 Sheets-Sheet 1 Filed June 26, 1959 3 R I m J l Q H n 0 N R R n M m f 1 f A 99:52 0 Ca m /,w H T3,; wwm ill? E I Oh y 21, 3 E. P. HARRIS 3,090,154

CUSHION AND METHOD OF MANUFACTURE Filed June 26, 1959 V 6 IIWIWTOR.

HIS ATTORNEY May 21, 1963 E. P. HARRIS cusuxou AND usmon 01-" MANUFACTURE Filed June 26} 1959 mmvron [Bk/4RD I? MIR/U5 4 Sheets-Sheet 3 HIS ATTOB/Vfy May 21, 1963 E. P. HARRIS 3,090,154

CUSHION AND METHOD OF MANUFACTURE Fi led June 26, 1959 4 Sheets-Sheet 4 [ow/mu I? mes/s (2% mmvrok.

HIS ATTORNH cushion including spring units United States Patent Motors Corporation, Detroit, Mich., a corporation of elaware Filed June 26, 1959, Ser. No. 823,160

3 Claims. (Cl. 45138) This invention relates to cushions and the like and is particularly directed to cushions including spring units and the methods for making the same.

It is an object of the invention to provide an improved wherein the spring units are independent of one another and are maintained in predetermined position within the cushion.

A further object of the inventionis to provide a method for making such a cushion.

In carrying out the above object, it is another and important object to provide a method whereby a spring cushion including a plurality of springs therein may be formed by setting all of the springs in a spring bank simultaneously against one surface of the cushion and adhering the springs in position while under compression 'whereby the cushion can be subsequently built up with the springs in predetermined position to one another without the use of interconnecting the rings whereby each spring is independently mounted and is capable of flexing without relation to any other spring.

The term cushion as used herein is understood to be sufiiciently broad to include seats, mattresses, and other articles which include spring filling to provide resiliency therein wherein the springs are applied simultaneously to a sheet-like element preferably of plastic, fabric or fibrous material such as burlap, sisal or the like.

Further objects and advantages of the present invention will be apparent from the following description; reference being had to the accompanying drawings wherein preferred embodiments of the present invention are clearly shown.

In the drawings:

FIGURE 1 shows a diagrammatic view of a portion of the apparatus used to supply springs to a plurality of spring supply manifolds.

FIGURE 2 is a diagrammatic view showing the end of one of the spring manifolds together with the apparatus for preparing a sheet of burlap for application of the springs thereto.

FIGURES 3, 4, 5 and 6 show one of a plurality of spring feeders used in the apparatus in various progressive positions for applying a spring to the burlap sheet.

FIGURE 7 is a plan view of a portion of a spring assembly.

FIGURE 8 is a section through line 88 of FIG- URE 7.

FIGURE 9 is a view similar to the opposite side of the URE 7 after application FIGURE 7 showing spring assembly shown in FIG- of a second wire frame. U FIIEGURE 10 is a view taken on line 10-10 of FIG- FIGURE 11 shows the application of resilient foam material to a spring assembly.

FIGURE 12 is a perspective view, a completed cushion, in this instance, cushion, and

FIGURE 13 is another embodiment of a cushion.

The production of seat cushions, mattresses and the like has always presented diflicult manufacturing problems, particularly in connection with the setting of the springs. In the past, these springs have been tied together progressively in one way or another, generally by hog rings wherein adjacent springs are tied together an automobile seat there is a greater interrelation between partly in section, of

to maintain them in spaced assembly. In some instances, the springs are tied on four sides thereof to adjacent springs and, in other instances, the springs are tied in longitudinal rows only. In either case, the hog tying operating is one of considerable expense and creates ditii'c'ult, manufacturing problems which have always been present. Furthermore, when the springs are tied together, 2; rings whereby, when one is spring flexed, it causes partig flexure of all associated springs that are tied thereto.

The difliculties are multiplied when on realizes that the average automotive seat, for. example, will require upwards to one hundred springs since it is imperative that the springs flex easily for a soft ride and that suflicient springs are included in the seat structure to support the weight of the occupants of the automobile in which the seat is installed. These problems are multiplied when mattresses are being manufactured since the area is larger and the number of springs is greatly increased.

The present invention is directed to a unique method for making cushions of all types wherein coil springs are used as the main resilient cushioning means and wherein said coil springs are applied without intertying of the springs and are positioned so as to be in side-by-side relation but substantially independent of one another. The application of the springs is further enhanced by the fact that the springs are fully attached to upper and lower sheet-like portions of the cushion 'whereby there is no opportunity for the springs to shift or to become loosened from their attached predetermined positions.

Another important feature of the invention relates to the setting of the springs. In conventional operations, each spring is tied to an adjacent spring by a progressive action and the springs are then connected to a peripheral wire or frame which holds all of them in position. This makes all springs more or less dependent upon one another. 'In the present invention, all springs for a given seat cushion may be set simultaneously in an adhesive base carried by a flexible sheet, for example, a sheet of burlap, sisal, impregnated paper, etc. In this instance, a sheet of burlap, for example, having an area about equal to the cross-sectional area of the cushion, is laid upon a supporting surface and a layer of an adhesive composition is applied thereto. Prior to the time that this adhesive is cured or hardened, the springs for the cushion are set simultaneously in the adhesive layer and are compressed simultaneously therein whereby each spring is adhered by the same amount of adhesive material and the same number of coils on each spring are immobilized within the adhesive material. This is of utmost importance since, when springs are separately applied by means of an adhesive, the degree of curing or hardening of the adhesive and the degree of pressure on the individual entire bank of springs. In this connection, it is sometimes desirable to tie each of the springs on the outside rows to the frame, all other springs being permitted to remain independent. The frame or border wire funcsprings 21 into a at any one time.

' the strip supply.

tions as a means againstwhich the cushion upholstery may be stitched.

In the next operation, the partially-formed spring bank is turned over with the framed side at the top and a sec-v ond frame is preferably positioned around the outside row of springs and attached thereto if desired. A foamy resilient material is next poured into the mold in predetermined quantities sufficient to cover the end portions of the springs and the frame to a predetermined depth. The foamy material, may be any suitable material such as a foamed flexible polyisocyanate, foam rubber or other elastomer. This foam is permitted to set or be cured whereupon the spring bank, with the attached cushion, is removed from the mold. This produces a finished cushion which may be covered as desired.

Specifically referring to the drawings, a diagrammatic view of an apparatus for winding and supplying springs is shown in FIGURE 1 wherein a conventional spring winder is shown at 20 which winds and ejects completed chute 22 which springs 21 are guided fall over mandrels 24 mounted on an endless. belt 26. The mandrels and speed of belt are timed in relation to the spring winder so that a mandrel 24 is directly under the chute 22 each. time a spring 21 is e'jected from the spring winder 20. The belt 26 with the spiings 21 thereon then passes through a stress relief oven 28 where the springs are suitably heated to relieve stress therein. The stress-relieved springs on the belt 26 next pass around a sprocket 30 and move downwardly in a generally vertical direction past the entrances of a plurality of chutes or feed tubes 32. As the springs 21 are in direct alignment of the mouths of the chutes 22, an ejecting mechanism is operated through a timer to eject the springs 21 into the mouths of the chutes 22. This ejecting mechanism may take the form of air jets as shown at 34 wherein the iets are operated each time the springs 21 upon mandrels 24 are in proper position with respect to the tubes or chutes 32. Any number of units such as the one shown in FIGURE 1 may be used to supply the mechanism for making the cushion. 'In this connection, if longer springs or difierent rate springs are required in portions of the cushions than in others, banks of chutes 32 may be used in connection with spring winders which produce springs of any desired type.

The springs 21 pass by gravity down the chutes 32 into spring supply manifolds 36 wherein one manifold 36 is shown in detail in FIGURES 2 through 6 wherein it will be noted that the manifold includes two feed pins 38 and 40 which are pneumatically or hydraulically operated. The upper pin 38 is positioned to permit one spring to pass and to hold the remainder of the supply of springs in the manifold from passing to the pin 40 whereby only one spring 21 can rest upon the pin 40 This is accomplished by withdrawal of the pin 38 to permit the supply of springs drop to the pin 40 whereupon the pin 38 passes through the second spring to hold the supply in the upper position so that, when the pin 40 is retracted, the lower spring by the chute and 21 is the only spring which will drop from the manifold.

A supporting strip or base 41, such as burlap, etc., is held on a roll 42 and is drawn therefrom by feed rollers 44. The burlap passes under an adhesive applicator 46 which depcsite a layer of an adhesive 48 on the surface of the burlap 41 which adhesive-coated hurlap then passes beneath the bank of feed manifolds 36 wherein one manifold is provided for each spring to be used in the cushion. The burlap strip 41 is then stopped in movement and is cut off from the main portion of At this time, all feed pins 40 are retracted simultaneously as shown in FIGURE 3 wherein one spring 21 from each manifold drops onto the adhesive layer 48 on the burlap 41. The pin 40 is again moved the lower chamber of the supply means with another spring. Thereupon, the pin 38 threads its way, through the second spring to hold the remainder of the springs in position. At this time, the entire manifold 36 moves downwardly whereby the pin 40, which is now in position across the manifold, bears on the top surface of the ejected spring 21 and compresses the spring and forces the lower coils thereof to become immobilized and submerged in the plastic layer 48. All manifolds 36 are depressed simultaneously whereby all springs 21 are compressed a like amount while the plastic or adhesive layer is in a mobile condition. The springs are preferably compressed by the manifold 36 for a desired period or until the adhesive layer at least partially sets or becomes hardened and, thereafter, the manifolds 36 are raised to the position shown in FIGURE 6 to permit the burlap backing 41 with all the springs adhered thereto to be drawn away from beneath the supply apparatus. Thereafter, the operation is repeated on another length of the adhesive-coated bur ap.

The burlap sheet 41 with the springs 21 attached thereto through the adhesive layer 48 may then pass through a curing oven or other curing means for completely setting the adhesive after which a frame 50 is applied around the free ends of the outer row of springs as shown in FIGURES 7 and 8. In this connection, the frame 50 is a wire which may be attached to the outer springs only, preferably by means of metal clips 52. The frame tends to stabilize the springs, improve the ease of upholstery thereof and maintain the cushion, after complete formation, to uniform dimensions by holding positively the outer rows of springs in position. The spring assembly is next inverted as shown in FIGURE 9 and a second frame 54 is applied to the other ends of the outer row of springs 21 by means of clips 56 which pass around the frame 54 and around the outer springs 21. The assembly is then in condition for the final operation wherein the free ends of the springs are embedded in an elastomer. For this operation, the spring bank assembly is positioned on the top surface 60 of a mold 62 with the springs depending downwardly into the lower portion 64 of the mold 62 which has previously been filled to a predetermined level with a resilient material such as latex foam, foamable polyisocyanate or other foamed elastomers, to form a layer of foamy resilient elastomer of a desired depth in the bottom portion 64 of the mold 62 and covers the end coils of the springs 21. After the foamy elastomer 66 is set or cured in accordance with the material being used, the entire cushion structure may be removed from the mold 62 for additional curing, if required, and will present a structure as shown at 70 wherein a foam cushion having a plurality of springs applied to a backing member is formed. It will be noted that, in FIGURE 12, the cushion 70 is shown partially cut away and, in this instance, it is possible to form the mold so that a front apron 72 of foamy material is integrally formed on the cushion during the molding step. a

The cushion may next be covered with suitable fabric or plastic and is ready for use.

Cushions formed by this invention not only are inexpensive to fabricate due to the absence of inter-tying of the springs but also the cost of manufacture is greatly reduced by the simultaneous immersion of all springs in one operation whereby all springs are applied first to the backing member for positioning the springs wherein the springs are applied under uniform pressures and then wherein all the springs are simultaneously attached to the cushion member in a single molding operation. Not only is a cushion of this character inexpensive to fabricate but it eliminates many of the variables heretofore present in cushion manufacture which lead to variable conditions within various cushions manufactured on a given machine.

It is to be understood that, where additional fabric layers are desired, such layers may be applied, for example, to the top surface of the springs, preferably prior to the application of the frame and the foam elastomer thereto. In this instance, it may be desirable to perforate the burlap or sisal or other material used so that the elastomer will fiow therethrough and embed the fabric therein. Similarly, the springs may be adhered to the second burlap layer as in connection with the first if desired or this second burlap layer may be merely stretched over the frame used to surround the outer springs of the spring bank. All of these variations come within the scope of this invention.

With respect to the adhesive used, it is desirable to use an epoxy resin normally termed a potting compound since this type of resin not only is tough but will cure into a nonbrittle layer which does not tend to break up and permit release of the springs from the fabric. Furthermore, the potting compound, upon application thereof, will ooze through the weave of the burlap, where a woven material is used, and firmly attach itself thereto to form an integral structure therewith or it will bond to plastic sheet material. This action is facilitated during the compression of the springs as shown in FIGURE 5 wherein the springs are pressed downwardly into the resin layer to force portions thereof into the coextensive contact with the backing and also assure embedding of the lower coils of the springs in the resin. During this period, the resin may be heated by infrared lights or hot air or other suitable means well known in the art, to cause at least a semihardening thereof.

In p ace of an epoxy resin, a layer of polyisocyanate can be applied to the backing.- This can be applied directly in a very thin layer. The springs are immediately placed therein and held compressed while the polyisocyanate foams or blows. This causes the polyisocyanate material to rise in the order of from four to nine times its original thickness in accordance with the formulation thereof whereby the bottom portions of the springs are enveloped with the material and are firmly attached to the burlap. This polyisocyanate material is of the flexible foam type as is well known in the art and forms no part of this invention. In most instances, however, it is similar to the material used to form the topper pad 70.

For example, suitable recipes for polyisocyanate materials used for adhering the springs and for the cushion are disclosed in U.S. Patent Re. 24,514 wherein Examples 1 and 2 thereof produce satisfactory foams. Wide variations may be practiced as is well known in the art.

The epoxy potting compounds may be chosen from a wide variety of commercial materials. For example, certain of the Epon resins sold by Shell Chemical Corporation are useful. Epon 828, 820 and 815, among others, may all be used. Full information on these resins will be found in Shell Technical Bulletin SC57-14, SC- 44 and Shell Technical Publications SC52-3 l, SC54-e46, etc.

The invention herein is not directed to the specific materials used, which are all well known in the art, but is directed to the application of the springs wherein all springs for a given cushion are set simultaneously or where entire banks or sections of springs are set simultaneously and are compressed simultaneously and uniformly during their, attachment to the backing sheet whereby a uniform spring bank is formed which maybe subsequently incorporated into a cushion, mattress or the like whereby a uniform product is obtained.

4 Where sections or banks of springs are set, the adhesive is only applied to portions where the springs are to be adhered. This procedure is useful in a large cushion 6 where each bank may include twenty-five to fifty springs and is also extremely useful where sections of the cushions include springs of different lengths or rates. In these instances, it is desirable to set all springs of a similar length or rate simultaneously whereby adjustments of the device are greatly facilitated. In place of fabric, or plastic sheet backing, it is sometimes desirable to use resin impregnated paper. This modification is useful .where a formed backing is desired. In this instance, the

impregnated paper is placed in a die and formed while the resin is being cured. This produces a contoured backing member wherein spring wire may be saved at portions of the seat that are not normally used through the application of shorter springs at these portions, etc. Such a seat is shown at 90 in FIGURE 13 having a contoured backing 91 wherein short springs 92 are used in conjunction with longer springs 94, 'wherein the frame wire 96'is held in a groove formed in thebacking and is not attached to the springs.

While the embodiment of the present invention as herein disclosed constitute preferred forms, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. In a method for producing a cushion including a. resilient topper pad and a plurality of predominately independent springs, the steps comprising; applying a layer of an adhesive in a mobile state upon one surface of a woven mat which adhesive is capable of subsequently becoming immobile, setting all of said independent springs to be used in the cushion simultaneously on said layer in predetermined position so that their end coils rest on said layer, uniformly compressing all of said springs for embedding said end coils only, into said layer, holding said springs in compressed position for a suflicient period to at least permit a change in mobility of said layer, and then completelyimmobilizing said layer for permanently attaching said springs to said mat.

2. In a method for producing a cushion including a resilient topper pad and a plurality of predominantly in-' dependent springs, the steps comprising; applying a layer of an adhesive in a mobile state upon one surface of a woven mat which adhesive is capable of subsequently be coming immobile, setting a plurality of springs simultaneously on said layer in predetermined position so that their end coils only rest in said predominantly imhependent layer, uniformly compressing all of said springs-for embedding said end coils into said layer and simultaneously forcing portions of the adhesive into coextensive relation with said woven mat, holding said springs in compressed position for a suflicient period to at least permit a change in mobility of said layer, completely immobilizing said layer for permanently attaching said springs to said mat, then inverting said mat and immersing a portion only of the other ends of said springs into a fluid foamy material, and curing said material into a. topper pad whereby a cushion is formed having a plurality of springs independently attached to a mat at one end thereof and to a topper pad at the opposite end thereof with free spring coils interposed between said points of attachment.

' 3. The method as claimed in claim 2 wherein the fluid foamy material is a polyurethane.

References Cited in the file of this patent UNITED STATES PATENTS Re. 24,914 Koenigsberg Dec. 20, 1960 1,963,710 Mitchell June 19, 1934 2,311,326 .Birkin Feb. 16, 1943 2,626,408 Wesley Ian. 27, 1953 2,716,308 Hodges Aug. 30, :1955 2,874,389 Koenigsberg 'Feb. 24, 1959 2,908,107 Williams Oct. 13, 1959 2,954,076 Crane et al. Sept. 27, 1960 

1. IN A METHOD FOR PRODUCING A CUSHION INCLUDING A RESILIENT TOPPER PAD AND A PLURALITY OF PREDOMINATELY INDEPENDENT SPRINGS, THE STEPS COMPRISING; APPLYING A LAYER OF AN ADHESIVE IN A MOBILE STATE UPON ONE SURFACE OF A WOVEN MAT WHICH ADHESIVE IS CAPABLE OF SUBSEQUENTLY BECOMING IMMOBILE, SETTING ALL OF SAID INDEPENDENT SPRINGS TO BE USED IN THE CUSHION SIMULTANEOUSLY ON SAID LAYER IN PREDETERMINED POSITION SO THAT THEIR ENDS COILS REST ON SAID LAYER, UNIFORMLY COMPRESSING ALL OF SAID SPRINGS FOR EMBEDDING SAID END COIL ONLY, INTO SAID LAYER, HOLDING SAID SPRINGS IN COMPRESSED POSITION FOR A SUFFICIENT PERIOD TO AT LEAST PERMIT A CHANGE IN MOBILITY OF SAID LAYER, AND THEN COMPLETE IMMOBILIZING SAID LAYER FOR PERMANENTLY ATTACHING SAID SPRINGS TO SAID MAT. 